So, now I am back at the novel I stopped reading because of the exam. I really like Wilde's style. The more I read it, the more I like it.

I found, however, a pair of sentences, whose construction I don't get completely. Here we go:

1)"I don't know that I shall tell you that, Mr Gray"
I suppose it means that the speaker doesn't know, whether he should tell something to Dorian. I don't understand why is it built in this fashion. Looking at it alone it seems as the speaker doesn't know whether he has to tell something to Dorian or not.
As a side question I would like to ask about the difference between "shall" and "will". Is it still respected at least partially in modern English? I mean also formal or literary English, not just colloquial speech of course.

2)"It posed the lad, made him more perfect as it were".
The lad is Dorian, and the sentence appears at the end of Harry's thoughts about Dorian's parentage. It means that his unfortunate parentage made him appear even more charming. As for the other sentence I don't understand completely the construction Wilde used. Especially that final "it + subjunctive (were)".

I'm just heading out for dinner and wanted to let you know that I've read your post and will answer tonight or tomorrow.

Certainly in 1) I would say that he does indeed know the answer but is telling his listener that he has not yet decided whether he will reveal it or not. He might be persuaded to tell the answer, then again, perhaps not. It's a very old-fashioned style of speaking.

Itikar wrote:So, now I am back at the novel I stopped reading because of the exam. I really like Wilde's style. The more I read it, the more I like it.

I found, however, a pair of sentences, whose construction I don't get completely. Here we go:

1)"I don't know that I shall tell you that, Mr Gray"
I suppose it means that the speaker doesn't know, whether he should tell something to Dorian. I don't understand why is it built in this fashion. Looking at it alone it seems as the speaker doesn't know whether he has to tell something to Dorian or not.

I agree with Calum "he does indeed know the answer but is telling his listener that he has not yet decided whether he will reveal it or not." This book was first published in 1890 so some of the wording may be "old fashion" to us.

Itikar wrote:As a side question I would like to ask about the difference between "shall" and "will". Is it still respected at least partially in modern English? I mean also formal or literary English, not just colloquial speech of course.

In most cases including your example "shall" and "will" are interchangeable. There are cases where "will" can be used but not "shall". Examples - to express a regular habit "She will climb out of the crib."; to express an expected result "He will run the mile in less than 4 minutes."; to express a strong desire or intention "He has the the will to win."

Itikar wrote:2)"It posed the lad, made him more perfect as it were".
The lad is Dorian, and the sentence appears at the end of Harry's thoughts about Dorian's parentage. It means that his unfortunate parentage made him appear even more charming. As for the other sentence I don't understand completely the construction Wilde used. Especially that final "it + subjunctive (were)".

Itikar wrote:
As a side question I would like to ask about the difference between "shall" and "will". Is it still respected at least partially in modern English? I mean also formal or literary English, not just colloquial speech of course.

Hardly anyone these days maintains, or is even aware of, the distinction between the modal verbs shall and will. When used as an indicator of a future event, they are more or less interchangeable nowadays.

The traditional rule in standard British English is that shall is used with first person pronouns (i.e. I and we) to form the future tense, while will is used with second and third person forms (i.e. you, he, she, it, they). For example:

I shall be late.
They will not have enough food.

However, when it comes to expressing a strong determination to do something, the roles are reversed: will is used with the first person, and shall with the second and third. For example:

I will not tolerate such behaviour.
You shall go to the ball!

In practice, though, the two words are used more or less interchangeably, and this is now an acceptable part of standard British and US English.

In my opinion the best one is the Oxford English Dictionary (electronic edition). Personally I am quite satisfied with the fourth version.

However in the public domain and for free you can get the (very) old edition of the Concise Oxford English Dictionary. It quotes less cognates in Dutch and Swedish in comparison to the modern Oxford but I think it shouldn't be so decisive.